Generally, a refrigerator is used to keep, for example, food at freezing or less or at a temperature slightly above freezing. The refrigerator includes a case, which defines an accommodation space divided into a freezing compartment and a refrigerating compartment, and devices, which constitute a refrigeration cycle to lower temperatures inside the freezing compartment and the refrigerating compartment, such as, for example, a compressor, a condenser, an evaporator, and an expansion valve.
Doors are mounted to one side of the case and serve to open or close the freezing compartment and the refrigerating compartment respectively.
In the configuration of the refrigerator described above, the refrigeration cycle cools air in such a manner that low-temperature and low-pressure gas-phase refrigerant is compressed into high-temperature and high-pressure gas-phase refrigerant by the compressor, the compressed high-temperature and high-pressure gas-phase refrigerant is cooled and condensed into high-temperature liquid-phase refrigerant while passing through the condenser, and the high-pressure liquid-phase refrigerant is reduced in temperature and pressure while passing through the expansion valve, and subsequently draws heat from the surroundings so as to cool the surrounding air while changing into low-temperature and low-pressure gas-phase refrigerant in the evaporator.
Efforts to improve the efficiency of operation of the refrigeration cycle of the refrigerator in order to reduce power consumption are being continuously conducted.